In an electronic component mounting apparatus, for example, there are driven a plurality of actuators 81 and 82 such as servomotors as shown in FIG. 32, and there is used a positioning control device 80 for controlling a position of a transfer head 85, that is an example of a movable body, with use of a ball screw and the like to move the transfer head 85 from an original position to an arbitrary target position. Here, from each parameter including a maximum velocity and a maximum acceleration, there is created a velocity change pattern, based on which the transfer head 85 is moved for implementation of positioning control.
Such conventional positioning control of a movable body is implemented by the positioning control device 80 composed of a mechanism portion mounting a positioning target or a transfer head 85, servomotors 81 and 82 for driving the mechanism portion, a main controller 90 for outputting a target position P2 for moving the transfer head 85 that exemplifies a movable body, a maximum velocity Vmax in movement, a maximum acceleration αmax in movement, and an operational start command C in movement, a positioning controller 91 for outputting a velocity command based on a given command, and servo drivers 92 and 93 for controlling drive of the servomotors 81 and 82 based on a given velocity command.
In the electronic component mounting apparatus incorporating the positioning control device 80, the transfer head 85 is positioned in an arbitrary position at planar coordinates with aid of a plurality of actuators 81 and 82 such as servomotors. For example, in moving the transfer head 85 from a planar coordinate P0 (original position) to a planar coordinate P2 (target position), if there is a region PAR that the transfer head 85 avoids passing in a linear travel route from the original position to the target position, positioning operation has been conducted by dividing the travel route into a route from the planar coordinate P0 to an operational passing position P1 and a route from the operational passing position P1 to the target position P2 as shown in FIGS. 32 and 33.
Herein, a travel distance between P0–P1 in X direction is referred to as X1, a travel distance between P0–P1 in Y direction as Y1, a travel distance between P1–P2 in X direction as X2, and a travel distance between P1–P2 in Y direction as Y2.
FIG. 34 shows a driving pattern of the transfer head 85 in this case. As shown in FIG. 34, each actuator such as a servomotor is tune-controlled so that timing of moving start and moving end between both P0–P1 and P1–P2 in X direction and Y direction is synchronous. In the route between P0–P1 where a travel amount in Y direction is large, movement in Y direction is implemented by driving with maximum acceleration αmax until a velocity reaches maximum velocity Vmax, whereas movement in X direction is implemented at a slower speed of Vmax×(X1/Y1). In the route between P1–P2 where a travel amount in X direction is large, movement in X direction is implemented by driving with maximum acceleration αmax until its velocity reaches the maximum velocity Vmax, whereas movement in Y direction is controlled to be implemented at a slower speed of Vmax×(Y2/X2). Consequently, driving is made in a state that movement of the transfer head 85 in either one direction is especially decelerated, resulting in longer driving time. Further, acceleration and deceleration operations conducted at the transfer passing position P1 increase power consumption.
As other positioning methods, there has been employed a method for moving from the original position P0 to the target position P2 via a middle passing position P1P, an operational passing position P1, and a middle passing position P2P by independently controlling respective actuators such as servomotors in each route between P0–P1 and between P1–P2 without synchronizing timing of moving end in X direction and Y direction as shown in FIGS. 35 and 36. In this method, driving is made with maximum acceleration αmax from the original position P0 to the middle passing position P1P both in X and Y direction until a velocity reaches maximum velocity Vmax. For movement in further Y direction from P1P to P1, driving is continuously made only in Y direction. At the operational passing position P1, movement in both X and Y direction is temporarily stopped. Then, driving is made with the maximum acceleration αmax from P1 to P2P both in X and Y direction until a velocity reaches the maximum velocity Vmax. For movement in further X direction from P2P to P2, driving is continuously made only in Y direction. Thus, control on movement to the target position P2 is implemented. Therefore, a driving velocity can be a maximum velocity with use of the maximum acceleration in each moving operation in place of increased frequency of stop and start operations, as well as prolonged driving time and enlarged power consumption as with the case of the above-stated method.
In the above-stated prior art, there are performed, in each case, two or more acceleration and deceleration operations, or stop and start operations, during movement, which may inhibit achievement of a maximum moving velocity. This prolongs moving operation time of the movable body and increases power consumption for driving, thereby preventing implementation of higher speed and power saving. In addition, in the latter case, there is an issue of requiring an expensive positioning control device for individual control of a plurality of actuators.
Accordingly, for solving these conventional issues, it is a first object of the present invention to provide a positioning control method and a positioning control device, which enable high speed positioning with low power consumption without repeating two or more acceleration and deceleration operations during movement from an original position to a target position.
It is a second object of the present invention to provide an electronic component mounting apparatus which makes it possible to mount electronic components for a short period of time through high speed positioning with low power consumption.